Process for preparing alkyl phenol sulfides



United States PROCESS FOR PREPARING ALKYL PHENGL SULFIDES No Drawing. Application February 21, 1955, Serial No. 489,780

3 Claims. (Cl. 25%-42.7.)

This invention relates to an improved process for preparing alkyl phenol sulfides. it particularly relates to the preparation of such sulfides by the reaction of alkyl phenols and sulfur halides in the presence of a saturated mineral lubricating oil which is essentially free of olefins and aromatic constituents.

Alkyl phenol sulfides have been conventionally produced by dissolving the alkyl phenol to be treated in a light low-boiling solvent such as carbon disulfide, ethylene dichloride, hexane and the like, and then treating the solution with a sulfur halide such as sulfur dichloride while removing the hydrogen chloride formed in the reaction. The solvent is then removed by stripping or distillation and the crude alkyl phenol sulfide is blended with a mineral lubricant base stock or other heavy solvent to facilitate further handling. The utilization of these low boiling solvents in the preparation of alkyl phenol sulfides requires facilities for stripping or distilling the solvent from the phenol sulfide product, as well as facilities for recovering the stripped or distilled low boiling solvent. In addition, a considerable amount of the solvent is lost during the process.

it has now been found that the preparation of alkyl phenol sulfides may be carried out in the presence of a saturated mineral lubricating oil which is essentially free of olefinic and aromatic constituents. The novel method or" this invention thereby eliminates the necessity of using a low boiring solvent in the reaction and thus eliminates the attendant facilities required therefor and the solvent losses resulting therefrom. in addition, an improved product is produced which forms metal salts having improved water sensitivity. In the improved method of this inver.ion, the saturated mineral lubricating oil performs a dual function formerly performed by the low-boiling solvent and the minerm lubricant base stock of the prior at. Heretofore it was not believed possible to carry out the preparation of alkyl phenol sulfides in the presence of a mineral lubricating oil due to the formation of considerable am unts of undesirable carbon and sludge in the reaction when utilizing conventional mineral lubricating oils.

HE SATURATED MINERAL LUBRICATING OILS refined mineral lubricating oils which have been sub- 6 jected to a high degree of solvent extraction or acid treating or a combination thereof.

The processes of solvent extraction and acid treating are well known in the art. Solvent extraction is carried u by co in h m ne l lubr ca i oi t 1- m su h a P l fatfgral, u fu diq ide ait han- 2a and h ik to th r b p e cl fi s a d Pa a atent 2,785,131 Patented Mar. 12, 1957 ice larly aromatic constituents from the mineral lubricating oil. Acid treating is generally carried out by adding fuming sulfuric acid to the mineral lubricating oil, separating the resultant sludge and extracting the oil from the sulfonic acids formed using hot water or dilute alcohol. The preferred saturated mineral lubricating oils useful in this invention are highly acid-treated oils prepared entirely by acid treating or by acid treating after phenol extraction. I

A convenient test for identifying saturated mineral lubricating oils useful in this invention is carried out as follows: 100 cc. of the mineral lubricating oil to be tested are placed in a beaker and 10 cc. of sulfur dichloride are added thereto. The mixture is stirred rapidly for three minutes. If no coke or sludge is formed at the end of three minutes, the oil may be utilized in the present invention. It will be understood that the expression saturated mineral lubricating oil essentially free of olefinic and aromatic constituents as used in this specification refers to an oil which forms essentially no coke nor sludge in the aforementioned sulfur dichloride test. Conventional mineral lubricating oils will form a considerable amount of coke and sludge and produce a black oil in the above described test.

The saturated mineral lubricating oils of this invention generally have an S. S. U. viscosity at 100F. of about 3.0 to 100 seconds and preferably about 50 to seconds. .Oils of lower viscosities are generally inadequate in their lubricating properties, whereas oils of higher viscosities are so viscous that essentially complete removal of by-product hydrogen halides therefrom is impractical. Preferably the saturated mineral lubricating .oils have a flash'point (Pensky Martens closed cup) above about 360 F. Particularly preferred saturated mineral lubricating oils useful in this invention are the white L ils or technical white oils of commerce.

THE REACTANT-S The present invention has particular application to alkyl phenols containing at least one alkyl group having in the range of 4 to 20 carbon atoms, preferably 6 to 18 carbon atoms. Preferred alkyl phenols contain one alkyl group per molecule. Specific phenols include tert. octyl phenol, nonyl phenol, amyl phenol and dodecyl phenol. Such phenolic materials are Well known in the art and form phenol sulfides that are soluble in mineral oils and the like. Mixtures of alkyl phenols may be used if ,desired. Suitable sulfur halides which may be used in the present invention include sulfur bromide, sulfur monochloride and sulfur dichloride, the latter being particularly preferred although mixtures may be used.

THE REACTION CONDITIONS In general, the preparation of alkyl phenol sulfides in accordance with this invention is carried out by dissolving the alkyl phenol in the saturated mineral lubrieating oil, adding the sulfur chloride or other halide to the oil solution of the alkyl phenol and removing the hydrogen chloride or other halide formed in the resultant reaction. Generally about 1 to 2 moles and preferably about 1.25 to 1.75 moles of the sulfur halide will be added per two moles of alkyl phenol. However, if desired, the ratio may vary rather widely in order to produce sulfides having from about 1 to 5 sulfur atoms interconnecting any two benzene nuclei. The amount of the saturated mineral lubricating oil employed should he sufiicient to provide a solution of the alkyl phenol, as well as a solution of the alkyl phenol sulfide product, which is sufficiently fluid to be'readily handled such as by pumping. In general, about 25% to 400% pref- 0 may ab0 l 5 to 200% b W t s d 9 th tatal reactants, will be employed.

solution of alkyl phenol to effect the desired reaction.

In general, the reaction will be essentially complete after a period of time of about 0.5 to 1 hour.

After the reaction is essentially complete, any byproduct hydrogen halide remaining in the oil solution of the alkyl phenol sulfide product is removed by any conventional means known to the art such as by water washing, by heat stripping or by gas blowing. Preferably the hydrogen halide is removed by blowing the oil solution with a gas such as air. This air-blowing step may be carried out at a temperature in the range of about 70 to 100 (3., preferably about 80 C. to 90 C. Essentially all of the hydrogen halide will be removed by air blowing at this temperature after a period of time in the range of about 0.1 to 1 hour. The alkyl sulfide products produced by the method of this invention are useful as oxidation inhibitors and are also useful as intermediates in preparing metal salts that are elfective detergent additives for lubricants. The invention will be more fully understood by reference to the following example. it is pointed out, however, that the example is given for the purpose of illustration only and is not to be construed as limiting the scope of the present invention in any way.

' Example The following saturated mineral lubricating oils were employed in the preparation of alkyl phenol sulfides in accordance with this invention:

Base oil AL-This base oil was a dewaxed and highly acid-treated parafiinic lubricating oil distillate having a S. S. U. viscosity at 100 F. of about 30 seconds and a flash point of about 180 F. Base oil A is a white oil of commerce and is sold under the trade name of Bayol D.

Base oil B.This base oil was a dewaxed and highly acid-treated parafiinic lubricating oil distillate having an S. S. U. viscosity at 100 F. of about 51 and a flash point of about 310 F. This base oil is also a white oil of commerce and is sold under the trade name of Bayol F.

Base oil C.This base oil was a dewaxed and highly acid-treated paraflinic lubricating oil distillate having an S. S. U. viscosity at 100 F. of about 88 and a flash point of about 350 F. This base oil is also a white oil of commerce and is sold under the trade name of Bayol 85.

Base oil D.This base oil was a dewaxed and acidtreated paraffinic lubricating oil distillate having an S. S. U. viscosity at 100 F. of about 89 and a flash point of about 335 F.

Base oil E.-This base oil was a dewaxed and acidtreated parafi'inic lubricating oil distillate having an S. S. U. viscosity at 100 F. of about 88 and a flash point of about 350 F. This base oil was identical to base oil C with the exception that it was not as highly acid-treated.

Base oils A, B, C, D and E when tested in the sulfur dichloride test set out heretofore in this specification produced no coke nor sludge. The addition of the sulfur dichloride in this test did produce a characteristic slightly red color (due to the solution of sulfur dichloride) in the oil but did not produce a black oil.

Each of the above-described base oils was then employed to prepare an alkyl phenol sulfide product in accordance with the present invention as follows: Two moles (434.4 grams) of diisobutyl phenol (also known as tert. octyl phenol) were charged "to a 3-neck 2-liter reactor containing 488.0 grams of the particular base oil used. To the resultant solution at 50-60 C. were added 1.6 moles (165 grams) of sulfur dichloride introduced over a 30-45 minute period. The heat of reaction was sufiicient to maintain this temperature without the use of heating or cooling. After 30 minutes of digestion, the temperature was raised to 90 C. while air blowing to remove hydrogen chloride fumes. This required about 30 minutes and produced an oil solution containing about 50 wt. of the tert. octyl phenol sulfide in the base oil. The properties of the oil solutions of phenol sulfide prepared as above are shown below in Table I. For comparison purposes, similar properties are also shown for a phenol sulfide product (in oil solution) prepared by a conventional procedure which comprised reacting the tert. octyl phenol with sulfur dichloride in the presence of hexane, stripping the hexane and hydrogen chloride from the alkyl phenol sulfide product and adding an equal volume of a diluent mineral lubricating oil (oil F). Oil F was a mildly phenol treated and solvent dewaxed mineral lubricating oil having an S. S. U. viscosity at F. of about 150 seconds. Oil F failed in the aforementioned sulfur dichloride test, producing a considerable amount of coke and sludge, and producing a black oil.

The following is a summary of the properties of the alkyl phenol sulfide products (tert. octyl phenol sulfide in oil solution) prepared in accordance with the present invention and by the conventional method:

1 Contain about 50 wt. percent of tart. octyl phenol sulfide and about; 50 wt. percent oil.

9 Tag-Robinson.

3 Cleveland Open Cup.

4 Conventional commercial preparation.

The alkyl phenol sulfide products (tert. octyl phenol sulfide in oil solution) shown in Table I were then utilized to prepare barium tert. octyl phenol sulfide products as follows: To the oil solution of the tert. octyl phenol sulfide was added Ba(Ol-I)2-5H2O at about C. The reaction mixture was digested for about 0.5 hour, the temperature raised to C. and the reaction mixture filtered. Additional oil was added at the beginning of this process to produce a final product containing about 40 wt. percent of barium tert. octyl phenol sulfide. The resultant products had the following properties:

TABLE II Properties of Barium Alkyl Phenol Sulfide Products 1 Base Oil Used Ba, S, H 0 8. S. 1 Wt. Wt. Color 2 Sens, Vis./210 F. Flash 3 Percent Percent cc.

A 10. 60 3. 7 9+ 15 283. 0 250 10. 50 3. 2 10 65 137. 9 355 9. 22 3. 4 9+ 20 143. 2 380 9. 10 3. 8 9+ 75 150.0 380 9. 60 3. 3 10. 5 30 121. 3 360 Hexane and Oil F 9. 90 3. 2 11 182.0 430 1 Contain about 40 wt. percent of barium tert. octyl phenol sulfide and about 60 wt. percent of oil.

Tag-Robinson.

3 Cleveland Open Cup.

4 Conventional preparation.

It will be noted that the water sensitivities of the barium tert. octyl phenol sulfides prepared in accordance with this invention were considerably better than that of the barium tert. octyl phenol sulfide prepared by the prior art method. More specifically, the water sensitivities of the products prepared by the method of the present invention were 75 or less as compared to 175 for the prior art product. The water sensitivities shown in Table II are the cc. of precipitate formed after 24 hours of standing from an oil composition containing 1 wt. percent of the particular additive (the metal 'alkyl phenol sulfide salt) and 1 wt. percent of water. It will be understood that the water sensitivities of any of these barium tert. octyl phenol sulfide products may be improved by treating them with carbon dioxide. The use of plasticizers, such as lauryl alcohol, in the preparation of these metal salts and/ or carbon dioxide treatment of the metal salts will reduce the viscosity of the final product and may be employed if desired.

The tert. octyl phenol sulfide products shown in Table l were also employed to prepare mixed calcium-barium tert. octyl phenol sulfide products as follows: Calcium hydroxide was added to the alkyl phenol sulfide product (tert. octyl phenol sulfide in oil solution) together with a small amount of isopropyl alcohol at about 60 C. After digestion for about 0.5 hour at 60 C., the temperature was raised to about 120 C. and Ba(Ol-I)z-5He0 was added. After digestion for about 0.5 hour, the temperature was raised to about 150 C. and the reaction mixture filtered. Additional oil was added at the beginning of this process to produce a final product containing about 40 wt. percent of calcium-barium tert. octyl phenol sulfide. The calcium-barium tert. octyl phenol sulfide products prepared from the tert. octyl phenol sulfide products of the present invention and of the prior art had the following properties:

TABLE III Calcium-Barium Alkyl Phenol Sulfide Products 1 Base Oil Used Ba, Ca, S, H O S. S. U., Wt. Wt. Wt. Color 1 Sens. Vis./2l0 Percent Percent Percent 1 Contain about 40 wt. percent of calcium-barium tert. octyl phenol sulfide and about 60 wt. percent oil.

1 Tag-Robinson.

3 Conventional preparation.

What is claimed is:

i. In a method for preparing mineral lubricating oil solutions of barium alkyl phenol sulfides, the improvement which comprises reacting alkyl phenol with sulfur chloride in the presence of a saturated acid-treated mineral lubricating oil essentially free of olefinic and aromatic constituents, wherein said lubricating oil is a white oil having a S. S. U. viscosity at 100 F. of about 30 to 100 seconds, and then preparing said barium alkyl phenol sulfide in the resultant white oil solution of alkyl phenol sulfide.

2. An improved method for preparing mineral lubricating oil solutions of barium alkyl phenol sulfides which comprises reacting alkyl phenol with sulfur chloride in the presence of a saturated acid-treated mineral lubricating oil, and blowing the reaction mixture with a gas to remove hydrogen chloride therefrom, said saturated acid-treated mineral lubricating oil being a white oil essentially free of olefinic and aromatic constituents and having a S. S. U. viscosity at 100 F. of about 30 to 100 seconds, and then preparing said barium phenol sulfide in the resultant white oil solution of alkyl phenol sulfide.

3. An improved method for preparing mineral lubrieating oil solutions of barium alkyl phenol sulfides which comprises reacting about 1 mole of tert. octyl phenol with about 0.5-1.0 mole of sulfur dichloride for about 0.5-1 hour at about 60 C., in the presence of about 50-20072; by weight, based on reactants, of an acidtreated mineral lubricating oil having a S. S. U. viscosity at lC=0 F. of about 50-9-0 seconds, and thereafter air blowing the resultant reactant mixture at a temperature of about 90 C. for about 0.1-1.0 hour until the reaction mixture is essentially free of hydrogen chloride, further reacting said reaction mixture with Ba(OH)z-5H2O and then filtering the reaction mixture to obtain a lubricating oil solution of barium tert. octyl phenol sulfide, said acidtreated mineral lubricating oil being a White oil essentially free of olefinic and aromatic constituents.

References Cited in the file of this patent UNITED STATES PATENTS 2,346,826 Cook et a1. Apr. 18, 1944 2,451,345 McNab et al. Oct. 12, 1948 2,472,517 Cantrell et a1. June 7, 1949 2,619,459 Neil Nov. 25, 1952 

1. IN A METHOD FOR PREPARING MINERAL LUBRICATING OIL SOLUTION OF BARIUM ALKYL PHENOL SULFIDES, THE IMPROVEMENT WHICH COMPRISES REACTING ALKYL PHENOL WITH SULFUR CHLORIDE IN THE PRESENCE OF A SATURATED ACID-TREATED MINERAL LUBRICATING OIL ESSENTIALLY FREE OF OLEFINIC AND AROMATIC CONSTITUENTS, WHEREIN SAID LUBRICATING OIL IS A WHITE OIL HAVING A S.S.U. VISCOSITY AT 100*F. OF ABOUT 30 TO 100 SECONDS, AND THEN PREPARING SAID BARIUM ALKYL PHENOL SULFIDE IN THE RESULTANT WHITE OIL SOLUTION OF ALKYL PHENOL SULFIDE. 